1. Field of the invention
The invention relates to photo-optical switches and keyboards and more particularly to single plane or monolithic photo-optical switch and keyboard apparatus.
2. Description of the Prior Art
Prior art electrical membrane switches have an electrically conductive coating on one side of each of two facing membranes which are normally separated but which may be brought into momentary contact as by operator finger pressure. When the two membranes are pressed together electrical contact is made between the two conductive surfaces or coatings. These conductive coatings have the disadvantage that they tend to radiate electromagnetic energy and are susceptible to electromagnetic interference (EMI).
It is therefore an object of the present invention to provide a photo-optical switch mechanism which avoids these problems while providing an efficient, fast acting, easily constructed fabricated and assembled switch assembly for use in keyboard arrays.
Still another object of the present invention is to provide a photo-optical switch mechanism which overcomes the EMI problems without measurably adding to the cost of construction and fabrication of the switching device.